Low-Field MRI as a Multiparametric Tool for Large Engineered Tissue Characterization.

Advances in 3D bioprinting have enabled the fabrication of large and complex engineered tissues, but their increasing size demands non-invasive tools for monitoring structure, maturation, and perfusion. Magnetic Resonance Imaging (MRI) offers unique multiparametric capabilities, yet high-field systems remain costly and inaccessible for most laboratories. In this study, we evaluate the potential of low-field MRI (LF MRI, 0.3 T) as an affordable and versatile alternative to high-field MRI (HF MRI, 7 T) for characterizing bioprinted tissue constructs. Using standardized PLA and hydrogel scaffolds within a custom-designed perfusion chamber, we compared LF and HF imaging performance for morphology and flow visualization. Both modalities successfully resolved internal scaffold features, with morphometric deviations from reference CAD models remaining within quality control tolerances. Flow imaging demonstrated that LF MRI could capture velocity distributions consistent with HF measurements and computational fluid dynamics simulations, even revealing fabrication-induced defects such as channel collapse or occlusion. Finally, we applied LF MRI for longitudinal monitoring of a perfused adipose tissue construct over 34 days. This approach enabled repeated non-destructive assessments of morphology and perfusion, with final histological analyses confirming homogeneous adipogenic differentiation and extracellular matrix deposition. Together, these results establish LF MRI as a powerful tool for real-time, non-invasive evaluation of biofabricated tissues. By combining affordability, portability, and multiparametric imaging capacity, LF MRI broadens access to advanced monitoring strategies in tissue engineering and regenerative medicine, supporting both quality control and functional assessment of large-scale engineered constructs.